A water main installed in the 19th century finally gave out late Friday night, resulting in rust-colored tap water throughout the city, according to a Department of Public Works official.

Water Division Supervisor Cathal O’Brien said the 20-inch break occurred at the Harris Street Pump Station

“It’s a water main from the 1800s that’s in our original treatment plans,” O’Brien said. “It’s pitch cast, so age [was the cause]. We immediately shut down the pump station. We shut down some valves to isolate the station. Once we got the valves closed, we immediately got pressure back to normal.”

O’Brien said it should not be a long-term problem for the city and that the pipe is not essential to the water system.

“As far as the city is concerned, it was fixed immediately,” he said. “We are abandoning a pipe. We don’t need it anymore.”

In the meantime, DPW workers will be flushing out the water system by opening up fire hydrants in different areas throughout the city, O’Brien said. The flushing will begin on dead end roads and areas with older water mains.

Although the problem affects the entire city, O’Brien said the flushing effort must start with the areas with the highest rust concentrations.

“We’re flushing the whole city, and if for some reason some sections are worse than others, if somebody is getting [rust] really bad, we’ll go out and go do it,”

O’Brien said. He noted that residents who live in areas that have already been flushed should call the DPW’s main line, 508-821-1431, if their faucets don’t run clear after a few minutes.

O’Brien said the flushing will continue until the rust problem is eliminated, but he couldn’t predict how long it would take.

“We don’t know because of the extent of the break,” he said. “Not sure. It was such a big break. It could take several days, at least, if not longer.”